Dictation system



Jan. 21, 1958 L. R. JONES ETAL.

DICTATION SYSTEM 5 Sheets-Sheet 2 Filed sept. 2o, 1954 FIG.

" 2mm, 195s R- JONES UAL 2,820,852

' DICTATION STEM l Filed sept. 2o.A 1954 5 sheets-sheet s" Fvic.

j m-usE lgaux-mol.

,40 l PULSE f2.3 mvENToRs X2 X! GENERATOR Lloyd R. Jones 448v y BQoug/as E. ofy/r 8.8i ma l 4888 f ATTORN Jan. 21, 1958 L. R. JONES ETAL A2,820,852

DICTATION SYSTEM Filed sept. 2o, 1954 5 sheets-sheet 4 FHG. lo.

CLUTCH FUNCTION 2Q/f 3/8 Q3-X TTENnAN-r TONE INVENTORS OSGILLA Lloyd R. Jones Dolly/a5 Ev Yay/or BY Jarl- 2 1, 1953 1 R. JONES Erm.

DICTATION SYSTEM 5 Sheets-Sheet 5 Filed Sept. 20, 1954 T m m M m w m w m4 M M E Il B 7 M Q 0 Z S4 H w 7 c w m A o 8 4 m 720 m 6 smw 6 l M w 6 i 3 FIG. le.

2,820,852 DICTATIGN SYSTEM Application September 20, 1954, Serial No. 457,165 22 Claims. (Cl.,17.9--100.1)

This invention relates to office-type dictation apparatus. More particularly, this invention relates to remotelyoperated dictation systems wherein a number of dictation stations are connected to central recording apparatus; and represents a further improvement in such central dictation systems as are disclosed and claimed in U. S. patent applications Serial Nos. 250,122 and 279,744, filed, respectively, on October 6, 1951, and April l, 1952, by D. E. Taylor and L. R. .Tones as joint inventors. The description herein is directed primarily to improvements over these earlier systems; for detailed information on other parts of the system, reference is made to the above applications.

For proper operation of a remote dictation system, it is important that the dictator as well as the central station attendant be provided with suitable controls and indicating devices'. For example, the dictator should be apprised when the system is ready for use, and should be provided with an exclusive chan-nel when dictating. Further, it is important for the dictator to be able to play back a portion of the recording, when desired, and to make marks on an indicator slip at the central machine to identify corrections, instructions and ends of letters for use in transcription.

It also is desirable for the dictator to be able to signal and talk to the central station attendant. Additionally, the dictator should be given an indication when the record is nearly used up, and the attendant should be timely notified of such a condition so that the record can be exchanged for fresh media. Moreover, such control and indication functions as mentioned above should be accomplished by the fewest number of inter-oce connections consistent with simple and economical circuitry.

Accordingly, it is an object of this invention to provide a central dictation system that is superior to those used heretofore. It is a further object of this invention to provide a central dictation system wherein the required indicating and control functions are carried by a minimum number of inter-cnice connections. Other objects, aspects and advantages of the invention will be apparent from, or pointed out in, the following description of a preferred embodiment considered together with the accompanying drawings in which:

Figure l (comprising Figures la through le) is a partial schematic View of a centalized telephone-operated dictation system, particularly showing those circuits required to explain the principles of the present invention;

Figure 2 is a schematic view of the privacy relay used with the system of Figure 1, showing the plug-jack connection arrangement; and

Figure 3 shows the dummy plug which may be substituted for the relay of Figure 2.` Y

The apparatus in the broken line block lll in the upper left hand corner of Figure la represents the equipment at one dictating station, it being understood that duplicates of this apparatus will be installed in-each of the oldces from which-dictating ,is to be done. These other dictating-stations will be connectedin parallel through -the interoice lines 12, 14, 16v and 18ito the centrally-positioned l United Stat@ Patent ice 2 control, recording and attendants station apparatus, Vindicated diagrarnmatically on the remainder of Figures -la through 1e. lt may be noted that all of the various control relays, to'be described in more detail hereinbelow, are shown in their deenergized condition.

To start dictation, Vwith the system in standby condition ti. e. power supplies and amplier filaments energized), the dictator lifts a telephone handset containing a receiver 20 and a transmitter 22, thereby opening one cradle-operated switch 24 and closing a second cradleoperated switch 26. This connects the microphone Vand the receiver to the inter-cnice lines V12 and 14, the path being traced from line 12 through a fixed contact 2S and movable arm 3d of a privacy relay 32, through a resistance-capacitance equalizing and D.-C. isolating network 34 and the receiver .20 (a parallel path being through a second resistance-capacitance network 36 and the transmitter 22), .through one xed contact 38 Vand a movable arm 4t) of an attendants call switch '42, through a movable rarm 44 and a tixed contact 46 of the privacy relay 32, and through a fixed contact 43 and movable arm 5t) of the cradle switch 26 back to the line 14. It should also be noted that, for purposes to be explained, a D.-C. path is completed between lines 12 and 142through a resistor 52 bridged across the network 36; this resist-or may have a value, for example, of about 4000 ohms.

One inter-ottico line 141s connected through an l-isolating capacitor 54 directly to one end of a primary winding 56 of an audio transformer 58. The other line 12 is connected through an isolation-capacitor 60, and through a fixed contact 62 and movable arm 64 of `a pulse relay 66 to the other end of the primary winding 56. The secondary winding .68 of the transformer 53 is connected by a shielded cable to two terminals of the usual recordreproduce switch, indicated diagrammatically -by the broken-line block 70, forming partof an amplifier assembly represented by a partial schematic diagram within the block 72. The audio signals thus fed into the amplifier assembly are amplified and recorded in the usual manner; the recording apparatus, being conventional, has been omitted from the drawing in order to simplify it. A reproducing head, generally indicated at 7-4, may be connected to the amplifier-assembly 72, through the switch 70, for play-back purposes as will be explained.

When lines 12 and 14 are connected together through the resistor 52, as mentioned above, current flows through the coils and 82 of a line relay 84. The current path may be traced from line 12 through a lead 86 and one relay coil 82, through a lead 88 to the positive terminal 9@ of a D.-C. power supply generally indicated by block 92 (and including, as do all of the D.C. power supplies referred to below, theV usual rectifying and liltering arrangements); from the negative terminal 94'of this power supply through a lead 96 and the other line relay coil t), through a lead 100 to line 14, and back to line 12 through the resistor 52. Because resistor 52 has a relatively high ohmic resistance, the current flow is insu'icient `to energize the line relay S4. However, the resulting voltage drop across the relay coil 80 raises the potential of lead 100, and, through a lead 192,.correspondinglyy raises the potential of thegrid 104 of a triode tube 106.

This tube 106 therefore starts to conductand energizes a record relay 10S, the current path being traced from theI anode 11d of tube 106, through the record relay coil 112 to the positive terminal 114 of a D.-C. power supply generally indicatedby block 118, and from the neutral terminal 116 of this power supply 118 to the-cathode '120 of the tube 106. The negative terminal 122 of the power supply 11S is connected to the negative terminal 94 of power supply 92, to provide the grid 104 of tube 106 with a negative cut-otf'bias except when'the line `relay.

S4 is energizedA as explained above,

relay 108 momentarily shortpath being completed from Energiza'tion of the record circuits lines 12 and 14, the line l2 through lead 86 and a lead 124, through a movablearm 126 and fixed contact 128 of the record relay, through a lfixed contact 130 and movable arm 132 of an in-use relay 134, and back along leads 102 and 100 `to line 14. This action shortsk out'the resistor 52, and connects the line relay coils 80 and 82 directly across the first power supply 92, thereby energizing the line relay 80. v

Operation of the line relay 84 applies power vto two in-use relays 134 and 136, the coils of which are in parallel. The energizing circuit may be traced from the negative terminal 138 of a D.C. power supply generally indicated by block 140, along a lead 142, through a movaiblearm 144 and iixed contact 14601? the line relay 84, through the parallel coils 148 and 150 of the in-use relays 134 and 136, and back along a lead 152 to a positive terminal 154 of the power supply 140.

Energization of the first in-use relay 134 opens up its contacts 130 and 132, and hence removes the short-circuit between inter-otiice lines 12 and 14 so that the current through the line relay 84 drops back to its previously low value (but high enough to maintain the line relay actuated). Correspondingly, contacts 158 and 160 of the iirst;inuse relay 134 open up to unshort a cathode biasing potentiometer 156, for the purposeof reducing the sensitivity of tube 106 so that it will cease conduction. That is, the resultant reduced current drain between terminals 116 and 122 of the --power supply 118 causes the potential between `these two terminals to increase (i. e. there is a lower drop across the power supply internal 'resistance). Hence, the cathode 120 is made more positive with respect to the grid 104, and tube 106 stops conduction and releases therecord relay 108. An additional cathode biasing potentiometer V162 is connected in series with potentiometer 156; adjustment of these two potentiometers permits a proper setting of the cathode bias such that tube 106 will conduct and cease conduction under the conditions outlined above.

It may be noted that although power supply 118 has been shown as anintegral unit, its operation may be more readily understod by. considering it,Y in etect, as two power supplies with their outputs connected in series. That is, terminal 114 is more positive than terminal 116, and terminal 116 is more positive than terminal 122. AOperation ofthe second in-use relay 136 energizes a hold relay 164, the current path being traced from the negative terminal 138 of the power supply 140 to the lead 142, through a lead 166, a xed contact 168 and movable arm 170 of the in-use relay 136, through a resistor 172 and winding 174 of the hold relay 164, and back a lead 176 to the positive terminal 154 of the power supply 140. This, in turn, applies power to the inter-office lines'16 and 18, the path being completed from the cated by block 180 to line 16, and from line 18 through a xed contact 182 and movable arm 184 of the hold relay 164, and thence to the positive terminal 186 of the power supply 180. The power on lines 16 and 18 energizes the dictators instrument lamp 188 (at all dictators stations) to indicate that the system is busy, the circuit being completedv from line 16, through a lead 190 and the lamp 188, and back through a lead 192 to line 18.

At the idle dictators stations, the cradle switches 24 and 26 will be unoperated (i. e. in the position shown in the drawing). Hence, the power on lines 16 and 18 will operate the corresponding privacy relays 32 at these stations, the circuit being completed from line 16, through lead 190 and the privacy relay winding 194, through a fixed contact 196 and movable arm 198 of the upper cradle switch 24, and back through lead 192 to line 18. Once the privacy relay 32 has been energized, it cannot be deenergized by operating the cradle switch, since the relay energizing circuit is then also completed through through e that, when it is substituted a movable arm 200 and fixed contact 202 of the privacy relay. The excluded dictator cannot interfere with operation of the system, since opening of the privacy relay contacts 44 and 46 disconnects the receiver 20 and microphone 22 from the talking lines 12and 14.

In addition, the excludedf dictator will hear a humming tone in his receiver, caused by the ripple -cornponent produced on lines 16 and 18 Vby the rectifier power supply 180, to notify him that the system already is'in use. This circuit may betraced from line 16 through a capacitor 204 and a-iixed contact 208 and movableearm 44 of the privacy relay 32, through the attendants call switch 42, the receiver 20, the equalizing network 34, through the movable arm 30 and a fixed contact 210 of the privacy relay, and back through a capacitor 214 and the lead 192 to line 18.

It has also been found advantageous vto providethe privacy relay 32 as a separate plug-in unit, so that the dictation system may readily bev transformed to. noueXclusive operation. Figure 2 shows, schematically, such an arrangement wherein the relay terminals are connected to corresponding terminals 'of a plug-jack combination generaly indicated at 33. Figure 3 shows, schematically, a dummy plug 35 having suitable jumper connections such for the relay 32 in Figure l, the dictation system will be rendered non-exclusive. In

effect, this dummy plug 35 permanently closesthe paths which, under the conditions outlined above, were completed through contact pairs 28-30 and 44446 of the privacy relay 32, and permanently leaves open all other relay contact paths. Thus, when' the dictator lifts up' his handset, actuation of the cradle switch 'connects' his telephone to lines 12 and 14 irrespective of whether dictator is already connected to these lines.

Reverting now to Figure l, the system also is arranged to provide a tone of short duration to the receiver of the telephone handset first picked up, to indicate to the dictator that he has taken control of the system. For this purpose, actuation of the second in-use relay 136 energizes a tone oscillator generally indicated by block 230, and which may be of any suitable type adapted to produce a signal, for example, of 1200 cycles per second. The energizing circuit for this oscillator 230 may be traced from its negative input terminal 232, through leadV 142 to the negative terminal 138 of the power supply 140; from the positive terminal 154 of this power supply, along lead 176, through a fixed contact 234 and movable arm 236 of a tone relay 216, through a fixed contact 238 and movable arm 240 of the second in-use relay 136, and back along a lead 242 and a lead 244 Vto the positive input terminal 246 ofthe tone oscillator 230. The signal produced by the oscillator 230 is coupled from `its output terminals 248 and 250, through two leads 252 and 254 and two isolation capacitors 256 and 258, to the lines 12 and 14, so that `the dictator on picking up his handset will hear the tone. and thus be notified that the system is ready for operation.Y

The tone relay 216 is maintained in energized condition (as long as 'the handsets are in their cradles) through a circuit which may be traced from the upper end of the tone relay winding 218, down through the lead 176 to the positive terminal 154 of the power supply 140, from the negative terminal 138 of the power supply to lead 142, and along a lead 220 through a xed contact 222 and movable arm 224 of the hold relay 164 back to the lower end of the tone relay winding 218. The tone relay 216, of course, loses its energization when the hold relay 164 is actuated in response to the lifting of a handset, because of the opening of hold relay contacts 222 and 224. The tone relay is, however, of the slow release type (eg g. Vit may be provided with a copper slug in the heel end'of the relay, and/or the relay winding may be bridged by a capacitor) which delays the opening of its contacts 234 t and 236 a length of time 1*-3 seconds) suicient for the dictator to hear the signal under normal circumstances.

Actuation of the hold relay 164 also applies power to a a' prior recording machine drive .motor 26h, .as kwell as to the rectier power supply which is diagrammatically indicated in the amplifier assembly 72 by a broken-line block 262, and which provides D.C. voltages for a clutch solenoid (to be described) and the anodes of the amplifier tubes (only partly shown). The power circuit for the drive motor 26h` may be traced from one A.C. inputterminal l 266, through a lead 26S and a lead 27d to a fixed contact 272 and movable arm 274 of the hold relay loll, through a lead 276 to the upper terminal of the motor 260, and from the lower motor terminal through an on-oli power switch 27S and a lead 239 back tothe other A.C. input terminal 282. Current for the power supply 262 is provided by a connection from lead 276 to one power supply input lterminal 234, the other .input terminal 286 being connected by a lead 288 to the power switch 27.3 and thence back to the A.C. terminal 232.

It may be noted that closure of the power switch 27S puts the system in standby condition with voltage supplied to the amplifier laments and a primary winding 29d of a power transformer 292, the secondary windings of which furnish A.C. voltage to the various relay power supplies partly described above. The filament power circuit may be traced from one A.C. input terminal 282 through lead 233, through the power switch 27S and lead 288 to the amplifier power supply input terminal 286, which is connected internally of the amplifier 72 to one end of the series-connected filaments 294, from the filament terminal 2% back to lead 263 and the other A.C. input terminal 256. The filaments 294- are bridged by a resistor 293 inV series with an indicator lamp 29S which glows when the filaments are 'energized to indicate that the system has been placed in standby condition. The transformervpower circuit is completed from the A.C. input terminal 256 through the transformer primary winding 29!) tol lead 253, through the power switch 278 and lead 250 back to the first A.C. input terminal 282.

Returning now to the operation of the system, when a person wishes to dictate, he presses a record switch 34MB, typically forming part of the telephone instrument, which shorts out the resistor 52 through an inductor 3tl2. lnductor 3M (e. g. l5() millihenries) in combination with the resistor and capacitor (e. g. 47 ohms and l0 microfarads) of network 36, prevents the dictator from hearing a painful click on closing his record switch.

The short-circuit on resistor 52 increases the current through the line relay Se, which as explained above makes the grid 104 of tube lilo more positive. Tube 196 therefore conducts and energizes the record relay ldd as previously described. @poration of this latter relay supplies power to a clutch relay 394 through a circuit which can be traced from the negative terminal T78 of the power supply ld, through a fixed contact 306 and movable arm 368 of the record relay i538, through a ixedcontact 310 and movable arm 312 of a normally-closed attendants relay Sll, through a lead 3l@ to one end of the clutch relay winding 318, and from the other end of this winding back along a lead 32. to the positive terminal 136 oi the power supply ld.

Actuation of the clutch relay 36d in turn closes the power circuit to a clutch solenoid 26d, and starts the recording head moving with respect to the record, both figuratively indicated at, respectively, 322 and 324. This circuit may be traced from a positive output terminal 326 of the amplier rectifier power supply 262, through a resistor 323 and the clutch solenoid winding 33?, along a lead 332, through a movable arm 334 and lixed Contact 336 of a normally-energized limit relay 333, through a fixed contact 34% and movable arm 342 of the clutch relay 35M, and along a lead 344 and lead 23S back to the negative terminal 286 of the amplifier power supply 262. Actuation of the clutch solenoid 264 also opens a switch 346 to remove a short circuit across the recording head coil thus placing the recording head into operative condition.

when the dictator desires te listen toa porties betnie material already recorded, he closes 'a' playback switch 350. One segment of this switch shorts out the 'resistor 52, through a movable arm 352 andfix'ed Contact 354, and therefore energizes the clutch solenoid in a 'manner as explained above with reference to the record switch 39u. The other segment of this switch 350 shorts together inter-ofiice lines i4 and 16, the path going from line' ld through the movable arm 50 and lixed Contact 43 of the cradle switch 26, through the lfixed Contact 46 and movable arm 44 of the privacy relay 32, through the movable arm Alil and ix'ed contact 3S of the attendants call switch 42, through a movable arm 356 and fixed con tact 33S of the lower playback switch segment, and back along a lead 359 to line 16.

Shorting lines ld and y16 furnishespower to control relay dell, thev current path being completed f'rin 'the positive terminal 364 of a D;C. power supply generally indicated by block 366, along a lead 363 and lead 1li() to line le, through the closed circuit described above to' line i6, along a lead 370, through a lixed Contact 372 and movable arm 374 ol' the hold relay 154, through the winding 37o of the control relay 362, and back along a lead 373 to the negative terminal 380 of the power supply 366. Cperation of the control relay 362 in turn energizes a function relay 332, the current path for this latter relay going rom the negative terminal 138of the power supply lati, along lead 142 and a lead 384, through a fixed contact 33d and movable arm 338 of the control relay, valong a lead 39) throughthc function relay winding 332, and back through lead l76 to the positive t'ci# minal 15.54 ci the power supply Ml).

lnergization of the function relay 382 applies power to a playback solenoid 394 which, by means not shown herein in order to simplify the disclosure, throws the record-reproduce switch 7l? to its reproduce position, lnvthe typical recording apparatus, a reproducing head (such as generally indicated at 74) engages the moving record a short distance behind the recording head, and when switch 'ill is in its reproduce position, the amplifier circuitry is arranged so that the signal played back from the record by the eproducing head is amplilied and' coupled through lines l2 and i4 to the dictators receiver ri`he energizing current path for the playback solenoid 3% may be traced from the positive terminal 326 of the amplifier power supply 262, through a resistor 396 and the playback solenoid winding 398, through a fixed contact all@ and movable arm 402 of the function relay 382, through the xed contact 340 and movable arm 342 of the clutch relay 318, along leads 344 and 238 back to the negative terminal 286 of the amplifier power supply 262.

When the dictator releases his playback switch, it is possible for the clutch relay 3&4 to drop out before the function relay 382 is released. Since this might produce an undesired result, e. g. place a mark on the indicator pad at the recording machine, means are provided for locking the clutch relay in until the function relay has dropped out. ing circuit which parallels contacts 366 and 308 of the record relay 1613, and which can be traced from Contact Btl-5, through a movable arm 133 and fixed contact- 135 of the first in-use relay 34, through a movable Varm 303 and fixed Contact 305 of the clutch relay 304,*through a movable arm 38E and fixed contact 383'of the function relay 382, and thence along lead 316 back to the clutch relay winding 318.

When the dictator desires to make a correction mark, or such, on the indicator pad typically provided at the recording machine, he actuates the Acorrection switch 404. The lower segment of this switch shorts out interoflice lines i4 and i6 through its fixed contact 406 and movable arm 408, in a manner similar to that explainedV above with reference tothe ,playback switch v350, and.cor1'e Tms is accomplished through an energizaangaan;

spondingly, energizes the function relay 382. A,In the uppersegment yof the correction switch, a movable arm 410 is disengaged from its 'xed contact 412,` and thereby 'assures -that operation'of the record switch 300 or playback switch 350, either accidentalor otherwise, will not shortcircuit the resistor 52. Consequently, the clutch relay 318 and clutch solenoid 264 cannot lne-energized when the correction switch 404 is depressed.

Operation of the function relay 382, in combination with deenergization of the clutch relay 318, applies power to ya marking relay 41,4 through a path which may be traced from the negative terminal 138 of the power supply 140, along lead 142 and a lead 416, through the marking relay winding 418, through a movable arm 420 and fixed contact 422 of the deenergized clutch relay 304, through a movable arm 424 and xed contact 426 of the energized function relay 382through a fixed contactl 428 and movable arm 430 of the second in-use relay 136, and thence back to the positive terminal 432 of theY power supply 140.

The marking relay 414, in turn, energizes a marking solenoid 612 through ya circuit which can be traced from a positive terminal 613 of the power supplylftl), through the relay contacts 413 and 415, through the solenoid winding 616, and back along leads 416 and 142 to the negative terminal138 of the power supply 149. Actuaticn of the marking solenoid 612, through means not showin herein, places a mark on an indicator pad at the recording machine. As outlined inthe above-mentioned U. S. patent application Serial No. 279,744, the relay 414 may be arranged so thatits actuation also removes a motionlimiting latch from the solenoid 612 to permit a somewhat longer mark to be made on the pad than when the solenoid is energized (as will be explained) independently of the relay 414. l

When the dictator desires to signal kthe attendant at the central station, he presses ra. button which transfers the Vmovable arm 40 of the attendants call switch 42 from the xed contact 38 to a second xed contact434.

This operation open-circuits lines 12 and 14 (since the conductive path previously passed through movable arm 40 and liXed contact 38 of switch 4?.).and at the same time closes a circuit from line 14 to line 16 in a manner similar to actuation'of thel correction switch 404 of the playback switch 356 as described above.

Opening the circuit between lines 12 and 14 in the dictators instrument deenergizes the line relay 84, and the consequent opening of line relay contacts 144 and 146 deenergizes the in-use relays 134 and 136 and thereby removes power from the hold relay winding 174. The

hold relay- 164 is, however, a slow releasek type (e. g. a copper slug'may be placed in the heel end of the relay, and a capacitor 175 may be connected in parallel with the relay winding 174), so that its contacts 372 and V374 remainclosedfor a short period of time (approximately 0.2 to 0.5 second). Thus, closing the circuit between lines 14 anclf16 energzes the control relay 362 through the current path previously described. As soon as the control relay pulls in, power is again supplied to the hold relay (thus maintaining both the hold relay and the control relay energized) through a path which can be traced from the positive terminal 154 of the power supply 140, through lead 176 tothe hold relay Winding 174, through a resistor 172, through the movable arm 170 and a fixed Contact 436 of the second in-use relay 136 (now deenergized), through the movable arm 388 and fixed contact 386 of the control relay 362, and back along leads 384 and 142 to thelnegative terminal 13S of the power supply 140. Actuation Vot` the control relay 362 .in turn energizes the, function relay 382 Vas previously described. The' function relay, when the in-use relays are deenergized, completes a circuit to a hummer 438 (located at the attendants' instrument generally indicated by a block 440'), which maybe any one of a variety of devices capable Vof producing an audible*signal'whenenergized n The .energizing circuit for the hummer 438 may 444 and xed contact 446 of theY function relay 382,

through a movable arm 448 and a fixed contact Y'45015015 Y' the normally-closed attendants relay 314, throughfafxed contact 452 Land movable arm 454 of thesecond' in-use relay 136 (now deenergized), throughthe hum.

mer winding 456, andback along a lead458 to a. lead .e X2 (which is connected to the other end of the trans-y e former secondary 'winding 442) y.

It will `be apparent from the above description'tliat' Y whether the dictator obtains playback, a correctionimarlr,V g

or signals the attendant `depends upon what .combina-r tion of relays are energizedalong with the control' relay v If the control relay is actuated before the desired 1 362. combination is fully set up, an error may result,.fe. 2g. a correction mark maybe obtained instead of playback. To avoid this possibility, the ,control relay advantageously is ofthe slow operate type .(e. grit may be provided with a copper slug in the armature end of. the relay).

Thus, there will be a small delay between energiza# tion and actuation ,(about 30 to 50 milliseconds)sul cient to assure that the proper combination ofotherl relays is established before the control relay pulls iin.A

The attendants instrument440 is provided with a telephone handset including a microphone 460 and a receiver 462, through which the attendant is enabledrlto converse with the dictator to receive instructions,e`tci When the hummer 438sounds, the attendantpc'ks up his handset, thereby actuating the attendants cradle switch 464.

The upper segment of thisfcradle switch 464-energizes` the attendants relay `314,'and also l*couples the-,attend-` ants telephone handsety to the dictators talking-circuit.

The relay power circuit may be traced from the'upper end of onev attendants relay winding 466, Valongga` lead 468, through the microphone 460 and a ksmall kresistor' 470, through a fixed contact 472 andfmovablearm .474 of the cradle switch 464, rvalong a lead476, throughfthe other attendantsrelay winding 478, along a lead480 to the negative terminal 94 of the powersupplyV 92, and from the positive power supply terminal 90 falong a lead l432 back to the lower end of the first attendants) Y relay winding 466. Closure of the upper segment ofthe cradle switchr464 places the microphone 460 (inseries with the resistor 470) andthe rreceiver 462(in`series with a capacitor 484 and a resistor 486) in vparallel across the leads 46S and 476; these two'leads,"in"'turn, are coupled `through respectivecapacitors 488 and 490 to the inter-oce lines 12 and 14 to complete the dictatorto-attendant talking circuit. f

Actuation ofthe attendants relay 314 removes power from'the hummer 438, by breaking the connection .bee tween movable arm 448 and fixed contact 450 of relay 314; i

To insure that `there is adequate line ,power for the dictator to 'talk to the attendant, it is desirablek forth'e dictator to press his record switch 360 and thereby Vshort Y out the series load'presented by the resistor 52.` Cloe Y sure of this switch 300 also will actuate the clutchsolei noid 264, even though energization of the attendants relay 314 opens up the previously-described solenoid power circuit through attendantsrelay contacts 310"and 312. This is because a parallel path aroundthese con'-v tacts is provided from the lower end of theclutch` relay winding 318, along leadk 458,1;hrough a movablearm 494Y and fixed contact 496 ofthe attendants cradle switch 464, through a movable arm 498 and fixed contact 500` of an attendants clutch switch 492,'and thence lbac tothe xed contact 310 of the attendants `relay 1314i- If the dictator desires-that the'conversation not'b'e ref corded, the attendant merely presses his clutch swit'elrJ 492 (which .preferably is spring-closed) toA open con: tacts 498 and 500, and thereby break the parallel clutch solenoid energizing circuit.

It may be desirable for the attendant to be notified when the dictator has nished dictating (i. e. hung up his handset) with only a few minutes time left on the record, so that fresh media can be placed on the machine. It also may be desirable to provide means for preventingany dictator from re-engaging the system when such little time is left on the record, since he might likely dictate to the end of the record without fully nishing his material, thus requiring an overlap between records. For this purpose, the recording machine carriage (not shown) is arranged to open an approach switch S02 when there is approximately two and one half minutes of time left on the record.

As long as the dictators handset is out of its cradle, opening of this approach switch 502 has no effect. This is because the open contacts 504 and 506 of this switch are still connected together by a parallel path -which can be traced through a lead 508, a'movable arm S10 and fixed contact 512 of the (energized) hold relay 164, through a fixed contact 514 and movable arm 516 of the normally-energized limit relay 332, and back along a lead 518 to the movable arm 506 of the approach switch 502. However, if the dictator hangs up While in the approach zone (i. e. while the approach switch is open), the consequent deenergization of the hold relay 164 will break this parallel circuit through hold relay contacts Slo and SlZ, and thereby deenergize the limit relay 338.

The limit relay, which is normally energized, receives its power from a circuit which can be traced from the negative terminal i233 of the power supply 140, along leads 142 and 416, through a limit switch 520, through one of two lever switches 522 and 524, through a movable arm 526 and fixed contact 52S of a normally-energized tube relay 53%, through the fixed contact 504 and movable arm 5% of the approach switch 502 (or through the parallel bridging path referred to above), along lead 518 to the limit relay winding 534, and from the other end of this winding back along lead 176 to the positive terminal ld of the power supply 140;

When both the approach switch 502 and its parallel bridging circuit through the hold relay 164 are opened, as when the dictator hangs up with the carriage in the approach zone, the limit relay will lose power and drop out. lf any dictator picks up his handset thereafter, the limit relay will not be reenergized, since the parallel path around the approach switch 502 is also broken 'by the opening of limit relay contacts 514 and 516. The limit relay may, of course, be reenergized by closing the approach switch 502, and means (not shown) may be provided for accomplishing this automatically if the attendant shifts the record-reproduce lever (not shown) at the central machine to its reproduce position.

As will be explained in more detail, deenergization of the limit relay 33S does the following: (l) places the recording machine in inoperative condition,` (2,) produces suitable indications at theattendants station to notify him of the status of the machine, and (3) energizes the instrument lamp SS at the dictators .stations to indicate that the system is not ready for use.

Opening of the limit relay contacts 334 and 336 breaks the power circuit (previously described) through which the clutch solenoid Zed is energized, thereby stopping movement of the record so thatthe machine is inoperative. The tone oscillator 230 is concurrently energized through a path which can be traced from the nega.- tive terminal 133 of the power supply 140, along lead 142 and a lead 540 to the negative input terminal 232 of the tone oscillator, from the oscillator positive input terminal 246 along lead 244, lthrough a lixed contact 542 and movable arm 544 of lthe limit relay 338, and

back along lead 176 to the positive terminal15d-ofthe` power supply 140. Correspondingly, the signalv pro-v duced by the tone oscillator is coupled to a loudspeaker 546 at the recording machine, this path being completed from one oscillator output terminal 54S, through -a movable arm 55h and fixed contact 552 of theV limit relay 33d to one terminal of the loudspeaker 546 (which is connected between one end and the sliding contactV of a volume-adjusting `potentiometer 554), and from the other end of the potentiometer 554 back through leads die and E42 and a lead 556 to the other oscillatcr output terminal 558.

The tone produced by the loudspeaker 546 notities the attendant that a recording machine is in need of attention. Since there may typically be a large number ofrecording machines at any one central installation, it also is desirable to furnish a light lsignal'at the particular machine concerned so that the attendant can quickly identify that machine. A neon lamp 560 is provided for this purpose, and is energized through a series resistor 562 and a parallel capacitor 564 to cause it to tiash periodically. The energizing circuit may be traced from onle lamp input terminal 566, along lead 142 to the negative terminal 133 of the power supply 140, from the positive power supply terminal 154 through lead 176 to the limit relay winding 534, and from the other end of this winding along lead 518 to the other'lamp input terminal 56d. lt may be noted that the neon lamp 56d is normally not energized because terminals 566 and 55S are shorted together through lead 416, limit switch 52d, either one of the lever switches 522 and 524-, tube relay contacts 526 and 52S, and the approach switch 592.

Deenergization of the limit relay 338 also provides a parallel bridging path around the hold relay contacts 82 and 134 so as to maintain the instrument lamp 188 at the dictator station energized when the handset is hung up. This path may be traced from hold relay contact iSd, through lead 329, through a fixed contact 183 and movable arm llSS of the limit relay 338, and back to hold relay contact 182.

Reverting now to the power circuit for the limit relay 338, it will be apparent that this circuit also will be broken if the limit switch 520 is opened, or if both of the lever switches 522 and 524 are opened, or if the tube relay contacts 526 and 528 are opened, and that the operations discussed immediately above will consequently occur under any of these conditions. The limit switch 526 is opened by motion of the recording machine carriage when it has reached the end of its travel; The lever switches 522 and 524 are controlled by the usual record-reproduce lever (not shown) at the central machine in such a way that one will be closed when this lever is in record position, the other will be closed when the lever is in reproduce position, and both will be open when the lever is in neutral position (as when the record is being changed).

The tube relay 53d is connected in series with the` catho-des of two tubes 576 and 572 in the iinal stage of amplification, and the flow of plate current through these tubes maintains the tube relay normally energized.

Should any of the ampliiier laments fail (which would automatically deenergize the series-connected laments of tubes 5743 and'572), or should the amplier not -be warmed up, the tube relay 53) will be deenergiz'ed.

Since as explained above plate voltage is not supplied to the amplier tubes when all the handsets are hung up, to prevent the consequent deenergiz'ation of the tube relay 53d from deenergiang the limit relayV and illuminating the dictators busy lamps in this situation, the tube relay contacts 526 and 528 are provided with a parallel bridging path from contact 528 along lead 508, through the movable arm 510 and fixed contact 574 of the hold relay, and back to the other tube relay contact 52H6. .Thus,'the' limitrelay will be energized throughftlle dcener'gized. hold relay. .Should any dictator pick.- up

hishandset, the limit relay willr be maintained in ener# gized condition throughthe tube relay contacts 526 and 528,'unless for somereason rthere is Ya failure of plate current through the final amplifier tubes 570 and 572.

Ifthe dictatorrhascdictated a substantial time in the approach `zone without hanging up, ,it is desirable to providezhimwith a warning indication 'that the end of the record is near. Accordingly, when there is about 30 to 60 seconds of time left on the record, the machine carriage closes a warning switch' 576 which completes the power circuit to a pulse generator generally indicated in block form at 578. VThis generator may be of the multivibrator type such as disclosed in the above-'mentioned U. S. patent application Serial lNo.,279,744, and produces short periodically spaced pulses between two output terminals 580 and 582. These pulses may, for example, havea duration of about.0.2 second, with a time between pulses of about 1.8 seconds. The, energizing circuit for thisvgenerator 578 may be traced from the negative terminal 138 ofthe power supply 146,- along leads 142 and 416, through the warning switchl 576 to one input terminal 534, and from the other input: terminal 586 to a positive terminal SSSgof the power supply 140.

, The pulses appearing -on the output terminals 580 and 582 periodically energize the pulse l(relay 66, the path going from one terminal S89 through a movable arm 59@ andxed Contact 592, of the rst in-use relay 134, through tshe pulse relay winding 594, and back to the other terminal The pulse relay 66, in turn, periodically energizes the tone oscillator 230 through a circuit which may be traced from positive terminal 154 of the power supply 140, through a lixed contact 596 and movable arm 598 of the pulse relay 66, along leads 242 and 244 tothe oscillator terminal 246, and from the other oscillator terminal232 through lead 142 to the negative terminal X38 of the power supply 140. As mentioned before, the tone oscillator signal (in this case, a periodic beep) is coupled from its output terminals 248 and 250 to the intcr-oice lines 12 and 14 and from there to the dictators receiver 20. The pulse relay also'is arranged to blank the recording machine during each beep, to prevent thev tone signal fromvbeing recorded. This is accomplished by shortcircuiting the audio transformer primary winding 56, the path going from the lower end of this winding, along a lead 600, through a fixed contact 6M and the movable arm 64hof the pulse relay 66, and thence back to the'otherV end of the audio transformer primary winding 56.

VVMeans, also are provided to enable the dictator to place an end-of-letter mark on the indicator pad at the recording machine by either hanging up his handset or manually operating his cradle switch. During dictation, energization of the hold relay 164 ycloses a circuit which charges a capacitor 664; this circuit can be traced from the positive terminal 154 of the power supply 140, through lead 176, a resistor 606, a iixed contact 66d and movable arm 610 of the hold relay 164 to one plate of the capacitor 604,

' and from the other capacitor plate through lead 142 back to the negativeV power supply terminal 136. When'the dictatorjhangs up, thus deen'ergizing hold relay 164, the capacitor 604 discharges through the marking solenoid 612, the current path going from hold relay movable arm 610 through a second fixed contact 614 to the solenoid ,winding 616, and back along leads 416 and 142 to the other end of the capacitor 694. As mentioned previously, this marking solenoid 612 may be provided with a motionlimiting latch controlled by themarking relay 414. When solenoid 612 is energized by the capacitor 604, this latch remains in place (since marking relay 414 will not be energized), and hence the solenoid movement will produce a relatively short mark on the indicator pad.V By @bienestar .the secretary transcribing the dictated material Llo Vis enabled to distinguish the` end-of-ltter*mark-trom the`I` longer correction mark.

Accordingly, it will be apparentthat the lapparatus dis-1 y closed herein achieves the several objects set forthabove. Although aspecific preferred embodiment of the invenapplications, itebeing understood that` various modifica*v tions maybe-madewithoutideparting from the scope' of.'v

the invention as limited by thefprior art. 'Weclaim:" M

l. For use with a remotely-operated dictation 4system which kincludes centrally located-recordingandcontrol apparatuswhe'rein a recording head'is arranged Vfor relaj tive traveling movement with respect to a record medium,V said systemralso including a plurality of dictators'stations any one of which may be'coupled to said recording head ,to transmitsound signals thereto for Yrecording on, said recordmedium, apparatus for enabling a plurality of conf` trol function'r'signals to be'transmitted overa minimumV number of interconnecting lines andlcomprising, incombnation, a plurality ofldictators instruments each including a microphone anda receiver, av control circuit for connecting said instruments -to said recording and control" apparatus, power supply means for producing current ow in 'said controll circuit, vv'control' means 'associated each of said instruments for selectively setting in discrete steps the magnitude of currentflow through said control circuit such that a plurality of current conditions may be established therein, current-energizable meansassociated` with said control circuit Iand -actuatable by the lcurrent liowing thereinwhen one of said current conditions is" established' but not actuatable by the Vcurrent flowing therein when 'other of said current conditions are -estab-` lished, the current-ow in said other conditions being .of

a lower magnitude than the current flow in said one con:

dition, operating means lunder the control of said currentenergizable means and arranged to be 'activated when one of said other current conditions is established and to subsequently actuate said current-energizable means `rby increasing'the-owof current therethrough, andrmeansy responsive to the actuation of saidv current-energizable means for changing the sensitivity of said operating means so asto deactivate said operating means and thereby reestablish said Vother current condition in said controlcircuit; whereby said operating means is made available. foi-.1'V

futureactivation and consequent operation of a predeterlv mined control-function when said one current condition is established in said control circuit by said control means.

2. For use wlthfa remotely-operated. dictation system which includes central control and recording' apparatus havingia Vrecording'head arranged forrelative traveling movement with-respect to a record medium, and'wherein Y one of'a plurality ofr dictators stations is to be coupled to said--recording'head to transmit sound signalsy thereto for recordingronrrsaid record medium, apparatus for iselectively relaying any one of a plurality of controlifuntion signals over aminimum number of interconnecting lines and-comprising, `in combination, a plurality of'dictators instruments. each including a microphone anda receiver, acontrol circuit for connecting said instruments to saidv recording and control apparatus, power supply means forprodu'cing current owin said control circuit,

control'means associated vwith each of said instruments for selectively setting in discrete steps the magnitude" of current flow. through said control circuitsuch that a plu#k rality of current conditions maybe established therein,

current-,energizable means associated with said controlgcin:

cuit andactuatable by the current owing therein when .one ,cisel-Current conditions is ,established .but .1101i A actuatable by the current flowing therein when other of said current conditions, are established, the current flow in said other conditions being of a lower magnitude than the current ilow in said one condition, operating means under the control of said current-energizable means and arranged to be activated when one of said other current conditions is established, means responsive to the activation of said operating means and arranged when actuated to increase the flow of current through said currentenergizable means and thereby to actuate the same, said current-energizable means being arranged when actuated to establish a iirst predetermined control function for said dictation system, and means responsive to the actuation of said current-energizable means for changing the sensitivity of said operating means so as to deactivate said operating means and reestablish said other current condition in said control circuit, saidl curreut-energizable means being arranged to remain actuated when said other current condition is reestablished, whereby said operating means is made available for future activation and consequent operation of a second predetermined control function when said one current condition is established in said control circuit by said control means.

3. ln a remotely-operated dictation system Which'includes central contro-l and recording apparatus having a recording head arranged for relative traveling movement with respect to a record medium, and wherein one of a plurality of dictators stations is to be coupled to said recording head to transmit sound signals thereto for recording on said record medium, apparatus comprising, in combination, a plurality of dictators instruments each including a microphone and a receiver, a control circuit for connecting said instruments to said recording and control apparatus, power supply means for producing current flow in said control circuit, control means associated with each of said instruments for selectively setting in discrete steps the magnitude of current fiow through said control circuit such that a. plurality of current conditions may be established therein, rst relay means associated with said control circuit and actuatable by the current flowing therein when one of said current conditions is established but not actuatable by the current owing therein when other of said current conditions are established, the current flow in said other conditions being of a lower magnitude than the current ow in said one condition, voltage-sensitive means connected to the winding of said rst relay means and arranged to be activated by the change in potential of said rst relay winding caused by the iiow of current therethrough when one of said other current conditions is established, second relay means energizable in response to the activation of said voltage-sensitive means and arranged when energized to increase the flow of current through said rst relay means by establishing said one current condition in said control circuit, said iirst relay means being arranged when energized to produce a rst predetermined control function in said dictation system, and means responsive to the actuation of said rst relay means for changing the sensitivity of said voltage-sensitive means so as to deactivate both said voltage-sensitive means and said second relay means and thereby reestablish said other current condition in said controlv circuit, said first relay means being adapted once energized to remain actuated by the ilow of current therethrough in said other current condition, whereby said voltage-sensitive means is made available for future activation and consequent operation -of a second predetermined control unction when said one current condition is established in said control circuit by said control means.

4. ln a remotely-operated dictation system which includes central control and recording apparatus having a recording head arranged for relative traveling movement with respect to a record medium, and wherein one of a plurality of dictators stationsl is to be coupled to said recording head to transmit sound signals thereto for recorolug on said record,l medium, apparatus comprising, in

combination, a plurality of dictators instruments each including a microphone and a receiver, va control circuit for connecting said instruments to said recording and control apparatus, powerk supply means for producing direct current ow in said control circuit, control means associated with each of said instruments for selectively setting in discrete steps the magnitude of current ilow through said control circuit such that -a plurality of current conditions may be established therein, iirs't relay means associated with said control circuit and actuatable by the current owing therein when one of said current conditions is established but not actuatable by the current liowing therein when other or" said current conditions are established, the current flow in said other conditions being of a lower magnitude than the current iiow in said one condition, a vacuum tube having a control grid connected to the winding of said lirst relay means, said tube being arranged to conduct current when the potential of said grid is raised by the ow of current through said winding when one of said other current conditions is established in said control circuit, second relay means energizabie in response to the ow of current through said tube and arranged when actuated to establish said one current con .ition in said control circuit so as to energize said lirst relay means, said rst relay means having a pair of contacts arranged when actuated to produce a first predetermined control function for said dictation system, and means responsive to the actuation of said first relay means and arranged to vary the grid bias on said tube so as to decrease the ow of current therethrough correspondingly deenergize said second relay means, said iirst relay means being adapted once energized to remain actuate by the ow of current therethrough in said other current condition, whereby said tube is made availabe for future activation and consequent operation of a secondH predetermined control function when said one current c is `established in said control circuit by said control means.

5. In a remotely-operated dictation system which includes central control and recording apparatus having a recording head arranged for relative traveling movement with respect to a record medium, and wherein one of a plurality of dictators stations is to be coupled to said recording head to transmit sound signals thereto for recording on said record medium, apparatus comprising, in lcombination, a plurality of dictators instruments each including a microphone and a receiver, a control circuit for connecting said instruments to said recording and control apparatus, power supply means for producing direct current ilow in said control circuit, resistance means associated with each of said instruments to be connected in series with said control circuit, first switch means associated with each of said instruments and adapted when actuated to connect said resistance in series with said control circuit to produce therein a current ilow of relatively low magnitude, second switch means associated with each of said instruments and adapted when actuated to short out said resistance means to increase the ilow of current through said control circuit, current-energizable means associated with said control circuit and actuata'ole by the current ilowing therein when said resistance means is shorted out but not actuatable by the current 'liowing therein when said resistance means is connected in series therewith, operating means under the control of said current-energizable means and arranged to he activated in response to the current ow therethrough when said resistance means is connected in series with said control circuit, said operating means being arranged when activated to short out said resistance vmeans and thereby to actuate said current-energizable means by the increased flow of current therethrough` said current-energizable means being adapted when 'actuated to produce a first predetermined control function for said dictation system, and means responsive to the actuation of said currentenergizable means for changing the sensitivity of said operating means so as `to deactivate said operating means cludes a central recording machine having a recording head arranged lfor relative traveling movement with respect to a record medium, and wherein one of a plurality of dlctators stations is to be coupled exclusively to said recording head to transmit sound signals thereto for re cording on said record medium, apparatus comprising, in combination, a plurality of dictators instruments each including a microphone and a receiver, on-oi switch meansfor each of said instruments, a communication cir' cuitrfor connecting any onev ofsaid instruments to said recording machine whenV the corresponding on-oi switch means is actuated, current-energizable means associated with each of said instruments and arrangedwhenenergized'to interrupt the connection `between saidcommunication circuit and the corresponding instrument, acontrol circuit for furnishing power ,to said current-energizable meansrupon operation of any one of said on-ot switch means, and meanstunder the control of each of said on-ot switch means tointerrupt the connection between said control circuit and the corresponding' current-energizable means upon operation of any one of said on-ott` switch means, whereby when the on-o switch means for one instrument is operated all of the current-energizable means will be actuated except at the said one instrument so 'that the said one instrument will have an exclusive 'channel to the recording machine through said communi- 'cation circuit.

7. In a remotely-operated dictation system which includes a central recording machine having a recording head arranged for relative ktraveling movement with respect to a record medium, and wherein one of a plurality of dictators stations is to be coupled exclusively to said recordinghead to transmit sound Ssignals thereto for *recording on said record medium,`apparatus, comprising, yin combination, a plurality of dictators instruments each including a microphone and a receiver, on-offrswitch means for each of said instruments, -a communication circuit for connecting any one of said instruments to said recording machine when the corresponding on-olf switch means is actuated, a relay associated with each kofsaid instruments and having a pair of contactsV adapted when said relay is energized to interrupt the connection between said communication circuit and the corresponding instrument, a control circuit arranged for connection to said relays, power supply means for producing current in said control circuit, means arranged upon operation of any one of said on-Oi switch means to connect said power supply means to said control circuit and to cause a ow of currentk therein, and second switch means mechanically joined to and operable with each of said ono switch means to interrupt the connection between'said control circuit and the associated relay upon operation of any one of said ori-oit switch means, whereby when the on-off switch means for one instrument is operated all of the relays will be energized except the relay at the said one instrument so that the said one instrument will have an exclusive channel to the recording t machine through saidV communication circuit.

8. In a remotely-operated dictation system which includes a central recording machine having are'cording head arranged for relative traveling movement with respect to a record medium, and wherein one of a plurality -of dictators stations is to be coupled exclusively vto said recording head to transmit sound signals thereto for recording on said record medium, apparatus comprising, in Combination, a plurality of Adictator's instruments each including a microphone and-a receiver, on-oi switch means forV each of vsaidinstruments, a communication circuit for connecting any oneof said instruments tosaid' recording machineV when the corresponding on-oli Vswitchl means is actuated, a relay associated with'eachofsaid'` instrumentsV and having a first pairfofcontacts arrangedY when said relay is energized to interrupt the connection' between said communication circuit and the corresponding instrument, a control circuit for furnishing power to said relays upon roperationo any one of said Vonfot switch means, means; under the control of each of saidA on-off switch .means to interrupt the connection between said control circuit and the corresponding relay `upon operation of Vany one ofsaid on-olfV switch means, a secondY pair of contacts vfor each of said relays `andoarranged` when the correspondingrelayis energized kto bypass said interrupting means to assure that said control circuit furnishes power to `said relay,rwhereby when the omolf switch means for one instrument isoperated all-.of .the

relayswill beV actuated except at the said one instrument` so that the said one instrument will have an exclusive..

channel to the recording machinethroughvsaid communi#V cation circuit and subsequent operation of any of the onoi switch means at other dictators stations will not deenergize the corres'pt'mdingV relay to connect such stationr y to the communication circuit. Y Y

9. In a remotely-operatedr dictation system whichin-vv cludes a central recording machine having Va recording head arranged for relative traveling movement with're-VV spect toa record medium, and wherein'one of a` plurality of dictators stations is'to lbe coupled exclusively to said recording head tov transmit sound signals theretoA for recording on said record medium, apparatus comprising, in combination, a plurality of dictators instruments each including a microphone and a receiver, on-oifswitch means for each of said instruments, a'communication circuit for connecting said instruments to said recording machine when the corresponding on-off switch means is actuated, a relay arranged to be inserted into a jack associated with each of said instruments, said relay having a pair of contacts adapted when said relay is'energized to interrupt the connection between said communication circuit and the correspondinginstrument,` a control circuit for furnishing powerl to said relayuponoperation of any one of said on-ol switch means,means under the control of each ofV said ori-off switch means to interrupt the connection between said control circuit andthe corresponding relay upon operation of any oneof said on-off switch means, whereby when the on-off switch means for one instrument is operated all of the relays will-be actuated except the'relay at the said oneinstrument so that the said oney instrument will. have an exclusive channel to Vthe recording machine through said'comniunicationY circuit, and adummy plug for said apparatus, said dummy plug being arranged to be inserted into said jack upon yremoval of said relay and having internal circuit connections for ixedly connecting said dictators instrument through said on-oi switch means to said communication circuit.

` l0..ln a remotely-operated dictation system which in.

cludes a central recording machine havingfa recordingk head arrangedforrelative traveling movement with re- -of dictators stations is to be coupled exclusively. tosaid Yrecording head to transmit sound signals thereto for recording on said record medium, apparatus comprising, Y

in combination, a plurality of dictators instrumentseach including a microphone and a n receiver, on-off switch means for each of said instruments, a communication circuit for connecting said instruments to said recording vtriachine when the corresponding on-off switch means Vis actuated, a relay associated with each of saidv instruments and having a pair of contacts arranged when said'relay is energized to interrupt the connection between said communication circuit and the correspondinginstrumenta 'control circuit for energizing saidrrelays uponoperation f of any one of said on-oiswitch means, rectier'power supply means connected to said control circuit to provide current thereto for the energization of said relays, means under the control of each of said on-ol switchrneans to interrupt the connection between said control circuit and the corresponding relay upon operation of any one of said on-od switch means, whereby when the ori-oft" switch means for one instrument is operated all of the relays will be actuated except the relay at the sai-d one instrument so that the said one instrument will have an exclusive channel to the recording machine through said communication circuit, and a second pair of contacts for each of said relays, said second pair of contacts being arranged when the corresponding relay is energized to couple said control circuit to the corresponding instrument so that an excluded dictator will be provided with a warning tone caused by the ripple component produced by said rectier power supply.

ll. For use with a dictation system wherein voice signals are to be transm ed over a communication circuit for recording by a centrally-located machine, and wherein a plurality' of system control functions may be operated remotely of said machine, apparatus comprising, in combination, a plurality of dictators instruments each including a receiver and a transmitter, a recording machine having a recording head arranged for relative traveling movement with respect to a record medium adapted to record voice signals, circuit means for connecting said instrumentstto said recording machine, said receiver and said transmitter being coupled to said circuit means, switch means associated with each of said instruments for selectively establishing any one of a plurality of current conditions in said circuit means, current-energizable means connected to said circuit meann and selec ively actuatable in accordance with the current condition established in said circuit means by said switch means, means under the control of said current-energizable means for producing the desired one of said system control functions in accordance'with .the condition of said current-energizable means, inductive means connected in series with said switch means, and serially-connected resistive and capacitive means bridged across said series-connected switch means and inductor means, whereby the sound impulse created in saidv instrument receiver upon operation ot'said switch means is substantially reduced.

l2. ln a remotely-operated dictation systern which includes central control and recording apparatus having a Aecording head arrangedtor'relati e traveling movement respect to a record medium, and wherein one of a plurality of dictators stations is to be coupled to said recording head to transmit sound signals thereto for recording on said record medium, apparatus for enabling any dictator to chose any one of several available system trol functions comprising, in combination, a plurality tators instrtunents each including a microphone and a rv lines for connecting said instruments to said recording and control apparatus, power supply means for producing current iiow through said lines, first manually-operable means at each one of said instruments for selectively controlling the current :dow through said first and second lines such that a plurality of current conditions may be established therein, second manually-operable means at each of said instruments for selectively controlling the current new through said second and third lines such that a plurality of current conditions may be established therein, and current-energizable means associated with said control apparatus and selectively responsive to lany of the various combinations ot'current conditions established in said rst, second and thirdk lines by thev selective operation of said lirst and second -i sans, and means operable in accordance with the selective response of saidv currentenergizable means and arranged to establish the desiredsysten1-ccurr-roly function V'in said recording Aand controlA apparatus,1

iver, first, second and third electrically-conductiveVV i3. in a :remotely-operated dictation system iwhich 'includes central-controland recording apparatushavin'g a recording head varranged for relative traveling movement with respect-to a record medium, and wherein one of a plurality of dictatorsstations 'is to be coupled to said recording head .to transmitsound signals thereto for recording on said record medium, vapparatus for producing any one of a plurality of'system control functions cornprising, in combination, -a plurality of dictators instruments each including a iriicropl'ione` and a receiver, rst, second and third lines for connecting said'instruments to said Vrecording andv 'control apparatus, saidI iirst and -secvond lines serving as a communication circuit for coupling said microphones receivers to said recording head, power snpplym'eans for producing current ow through said lines, Yirst 'switchfmeansate'a'ch one ofs'aid instruments for selectivelycontr'olling the current flow through said tiret and second lines such that a plurality of current conditions may be 'established therein, second switch means at eachof said instruments for selectively controlling the current flow through said second and third lines such that a plurality of current conditions may be'established therein, and a plurality of relays associated with said control apparatus and selectively energizable in response to the particular combination of current conditions established yin said rst, second and third lines in conformance with'theselected positioning of said iirst and second switch means, and control means operable in accordance with the vselective energization of said relays and arranged to accomplish the desired system control function in said recording and control apparatus.

le. ln' a remotely-operated dictation system which includes central 'control and recording apparatus having a recording head arranged for relative traveling movement with respect to a record medium, and wherein one of a plurality of dictators stations is to be coupled to said recording head to transmit sound signals thereto for recording on said record medi-drm apparatus for selectively establishing any one of a plurality of available system control iunctions and'comprising, in combination, a plurality of dictators instruments each including a microphone and a receiver, iirst, second and third lines for connecting said instruments to said recording and. control apparatus, said lirst and second lines serving as a communication circuit between said instruments and said recording apparatus, power supply means for producing direct current ow through said lines, rst manually-operablel switch means at each one of said instruments for selectively con-v trolling the current llow through said rst and secondy lines such that any one of three current conditions may be established therein, second manually-operable switch means at each of said instruments for selectively controlling the current ow through said second and third lines such that either of two current conditions maybe established therein, and relay means associated with said control apparatus and selectively energizable in accordance with any particular one of the'six possible combinations of current conditions established in said iirst, second and third lines-by the selective control of said first and second switch means, and control means associated with said recording apparatus and loperable in accordance with the selective energization of said relay means, said control means being arranged to produce the desired system control function in said recording and control apparatus in conformance with the setting or said rst and second switch means.

l5. In a remotely-operated dictation system which includes ycentral control and recording apparatus having Va recording head arranged for relative traveling movement establishing any one of a plurality `of available system resistance means associated with each of said instruments and adapted for connection to saidri'irst and second lines, rst switch means at each one of said instruments for connecting said resistance means in series with said first and second lines to produce therein a current flow of relatively low magnitude, second switch means at each one of said instruments for shorting out said resistance means to produce in said first and second lines a current liow yof relatively greater magnitude than when said resistance means is in series with said first and second lines, third switch means at each one of said instruments and arranged when actuated to short together said second and third lines to cause a ow of current therein, and currentenergizable means in said control apparatus selectively responsive to any of the various combinations of current conditions established in said first, second and third lines by the selected positioning of -said first, second and third switch means, and control means operable in accordance with the selective response of said current-energizable means and arranged to establish the desired system control function in said recording and controljapparatus in conformance with the positioning of said first, second and third switch means. f

16. In a remotely-operated dictation system which includes central control and recording apparatus having a recording head arranged for relative traveling movement with respect to a record medium, and wherein one of a plurality of dictators stationsris to be coupled to said recording head to transmit sound signals thereto for recording on said record medium, apparatus for selectively establishing any one of a plurality of available system control functions and comprising, in combination, a plurality of dictators instruments each including a microphone and a receiver, rst, second, third and fourth lines for connecting said instruments to said recording and control apparatus,v said rstr and second lines serving as a communication circuit between said instruments and said recording apparatus, power supply means for producing direct current flow through said lines, indicator lamp means at eachone of said instruments and connectible to said third and fourth lines, said indi-cater klamp means being arranged upon energization oft-said third and fourth lines to provide a light signal at said instrumentsto indicate that the dictation system is in use, liirst manually-operable switch means at each one of said instruments for selectively controlling the directV current flow through said first and second lines such that a plurality of current conditions may be established therein, second manually-operable switch means at each of said instruments for selectively controlling the current ilow through said secondand third lines such that a plurality of current conditions may be established therein, and current-energizable means forming a part of said control apparatus and selectively responsive to any of the various combinations of Vcurrent conditions established in said rhst, second and third lines by the selected positioning of said rst and second switch means, said current-energizable means including means adapted when current flows through either said rst and second .lines or said second andV third lines to energize Vsaid third and fourth lines and thereby to light said indicator lamp,-and means operable inraccordancewith thev selective response of rsaid currentenergizable means and arranged to establishv the desired system control-function in Asaidrecording and control apparatus. t

17. Ina remotely-operated dictation ysystem whchincludes .a central recordingdmachine having a lrecording t head arranged "for 'relative traveling yfrnv'ennientTivithre'- spect to a record medium, and wherein oizieoii` plurality of dictators stations stoj'oe coupldetclusivly toi said recording head totransmit soundsignalslthere't'for -re-l cording on said record medium, apparatus comprising, in,Y combination, a plurality. of` dictators instruments 'eachincluding a microphone and a receiver, on-ot switch meansrfor each of said instruments, jexcommunicationVV circuit for connecting any. one of said instruments to said recording machine when the correspondingon-ot switch means is actuated, a relay associated with-eachof said f' instruments and having la first pair.ofcontactsj-arranged when said relay is energizedfto interrupt the connectionY between said communication-.circuit and the lcorresponding instrument, a control-circuit forfurnishing-powery to said relays upon operation of anyone: of said bri-oit switch means, means under the control-of each orisaid on-oft switch means to interrupt the connection betweenI said control circuit and the corresponding relay upon operation of Vany one of said'on-o switch means,a sec-y ond pair of contacts for each of said relays and arranged when the corresponding relay is energized to by-pass said interrupting means Vto assure thatv said control circuit con- Ytiriues to furnish power to said relay, whereby whenithe on-otl switch means for one instrument is operated all of the relays will bevactuatcd exceptat the saidone in-vr strument so that the said one instrument will have an` exclusive channel to the recording Vmachine through said communication circuit and subsequent operation ofanyf' of the on-oi switch means at other dictators stations.-

will not de-energize the corresponding relay to connect such station to the communication circuit, and indicating l light means associated "with said control circuitV to indicate whether the dictation system is intuse.:

18. In a remotely-operated rdictation systemrwhich Vincludes a central recording machine having a recording head arranged for relative traveling movement `with re` t spect to a record medium, and wherein one ofV a plurality of dictators stations is to be ,coupled exclusively to said recording head to transmit sound signals thereto for re-` cording on said record medium, apparatus comprising, kin v combination, a plurality ofdictators instruments each including a microphone and a receiver, on-oi switch means for each of said instruments, a communication circuit for connecting said instruments to said recordingy machine when the'correspondingron-off switch'meansis actuated, a relay associated with each of said instruments and having a pair'of contacts arranged whensaidrelay is energized to interrupt the connection between said communication circuit and the correspondinginstrument, a control circuit for energizing said relays upon operation of any one of said on-off switch Vmeans, rectifier power supply means connected to said control circuit to provide current thereto for the energization of said relays, means Y underthe control ofeach of said on-ofr` switch means toV interrupt theconnection between said controlcircuiftzand the corresponding `relay upon operation of, any one ofV said on-o switch means, whereby wh'enthe on-oi switch means for one instrumentV isoperated all of the relays will be actuated except the relay at the said one instrument so that the said one instrument will have an exclusive channel to the recording machine through-said communication circuit, and a second pair of contacts for each of ,said relays, said second pair of contacts being arranged when the corresponding relay is energized to couple the corresponding instrument to a source of tone signals sok that an excluded dictator will be provided with a warning tone to indicate that the dictation' system is in useff 'n 19. For use with a dictation system wherein voice sig-` Y l nals are to be transmitted over a communication circuit' for recordingfbya centrally-located machine, and'whereo in a plurality of system control Vfunctionsrmay be'operated remotely of said machine, apparatus comprising,. Y in combination, a plurality of dictators instrumentsfeach f including a receiver and a transmitter, a recording. nia-"i Y,

chine having a recording head arranged for relative traveling movement with respect to a record medium adapted to record voice signals, circuit means for connecting said instruments to said recording machine, said receiver and said transmitter being coupled to said circuit means, switch means associated with each of said instruments for selectively establishing any one of a plurality of current conditions in said circuit means, current-energizable means connected to said circuit means and selectively actuatable in accordance with the current condition established in said circuit means by said switch means, means under the control of said current-energizable means for producing the desired one of said system control functions in accordance with the condition of said currentenergizable means, inductive means connected in series with said switch means, capacitive means bridged across said series-connected switch means and inductor means, and resistance means conneced in series with the circuit formed by said inductor and capacitive means, whereby the sound impulse created in said instrument receiver upon operation of said switch means is substantially reduced.

20. In a remotely-operated dictation system which includes central control and recording apparatus having a recording head arranged for relative traveling movement with respect to a record medium, and wherein one of a plurality of dictators stations is to be coupled to said recording head to transmit sound signals thereto for recording on said record medium, apparatus for enabling any dictator to choose any one of several available system control functions comprising, in combination, a plurality of dictators instruments each including a microphone and a receiver, first, second and third electricallyconductive lines for connecting said instruments to said recording and control apparatus, power supply means for producing current ow through said lines, a plurality of switches interconnected with said first, second, and third lines for controlling the current flow through said lines such that a plurality of current conditions may selectively be established therein, a plurality of manually-operable mechanisms associated with said switches and arranged in such a manner that actuation of any one of said mechanisms will operate a predetermined combination of said switches and establish a corresponding combination of current ow conditions in said first, second and third lines, current-energizable means associated with said control apparatus and selectively responsive to any of the Various combinations of current conditions established in said first, second and third lines by the selective operation of said switches, and means operable in accordance with the selective response of said current-energizable means and arranged to establish the desired system control function in said recording and control apparatus.

21. In a remotely-operated dictation system which includes central control and recording apparatus having a recording head arranged for relative traveling movement with respect to a record medium, and wherein one of a plurality of dictators stations is to be coupled to said recording head to transmit sound signals thereto for recording on said record medium, apparatus for selectively establishing any one of a plurality of available system control functions and comprising, in combination, a plurality of dictators instruments each including a microphone and a receiver, first, second and third lines for connecting said instruments to said recording and control apparatus, said first and second lines serving as a communication circuit between said instruments and said recording apparatus, power supply means for producing direct current flow through said lines, first manually-operable switch means including a plurality of separate switches at each one of said instruments for selectively controlling the current ow through said first and second lines such that any one of three current conditions may be established therein, second manually-operable switch means at each of said instruments for selectively controiling the current ow through said second and third lines such that either of two current conditions may be established therein, a plurality of manually-operable mechanisms interlinked with said first and second switch means and arranged in such a manner that actuation of any one of said mechanisms will operate a predetermined combination of the switches and establish a corresponding combination of current flow conditions in said first, second and third lines, relay means associated with said control apparatus and selectively energizable in accordance with any particular one of the six possible combinations of current conditions established in said first, second and third lines by the selective control of said first and second switch means, and control means associated with said recording apparatus and operable in accordance with the selective energization of said relay means, said control means being arranged to produce the desired system control function in said recording and control apparatus in conformance with the operation of said first and second switch means by the selected one of said manually-operable mechanisms.

22. In a remotely-operated dictation system which in cludes central control and recording apparatus having a recording head arranged for relative traveling movement with respect to a record medium, and wherein one of a plurality of dictators stations is to be coupled to said recording head to transmit sound signals thereto for recording on said record medium, apparatus for selectively establishing any one of a plurality of available system control functions and comprising, in combination, a plurality of dictators instruments each including a microphone and a receiver, first, second, third and fourth lines for connecting said instruments to said recording and control apparatus, said first and second lines serving as a communication circuit between said instruments and said recording apparatus, power supply means for producing current fiow through said lines, indicator lamp means at each one of said instruments and connectible to said third and fourth lines, said indicator lamp means being arranged upon energization of said third and fourth lines to provide a light signal at said instruments to indicate whether the dictation system is in use, first switch means including a plurality of separate switches at each one of said instruments for selectively controlling the direct current flow through said first and second lines such that a plurality of current conditions may be established therein, second switch means at each of said instruments for selectively controlling the current fiow through said second and third lines such that a plurality of current conditions may be established therein, a plurality of manually-operable mechanisms interlinked with said first and second switch means and arranged in such a manner that actuation of any one of said mechanisms will operate a predetermined combination of the switches and establish a corresponding combination of current flow conditions in said first, second and third lines, current-energizable means forming a part of said control apparatus and selectively responsive to any of the various combinations of current conditions established in said first, second and third lines by the positioning of said first and second switch means in accordance with the selective actuation of any one of said manually'- operable mechanisms, said current-energizable means further including means adapted to control the energization of said third and fourth lines and said indicator lamp, and means operable in accordance with the selective response of said current-energizable means and arranged to establish the desired system control function in said recording and control apparatus.

References Cited in the file of this patent UNITED STATES PATENTS 2,066,672 Bernard et al Jan. 5, 1937 2,277,207 Chenoweth et al Mar. 24, 1942 2,677,018 Logan Apr. 27, 1954 2,690,480 Logan Sept. 28, 1954 

